2 1 Variablesand and Expressions Warm Up Problem

2 -1 Variablesand and. Expressions Warm Up Problem of the Day Lesson Presentation Course 11 Course

2 -1 Variables and Expressions Warm Up Simplify. 1. 4 + 7 3 1 2. 87 15 5 3. 6(9 + 2) + 7 4. 35 7 5 Course 1

2 -1 Variables and Expressions Problem of the Day How can the digits 1 through 5 be arranged in the boxes to make the greatest product? Course 1

2 -1 Variables and Expressions Learn to identify and evaluate expressions. Course 1

2 -1 Variables and Expressions Vocabulary variable constant algebraic expression Course 1

2 -1 Variables and Expressions A variable is a letter or symbol that represents a quantity that can change. A constant is a quantity that does not change. Course 1

2 -1 Variables and Expressions An algebraic expression contains one or more variables and may contain operation symbols. So p 7 is an algebraic expression. Algebraic Expressions 150 + y 35 w + z NOT Algebraic Expressions 85 ÷ 5 10 + 3 5 To evaluate an algebraic expression, substitute a number for the variable and then find the value. Course 1

2 -1 Variables and Expressions Additional Example 1 A: Evaluating Algebraic Expressions Evaluate the expression to find the missing values in the table. y 5 y 16 80 Substitute for y in 5 y. y = 16; 5 16 = 80 27 y = 27; 5 27 = 35 y = 35; 5 35 = The missing values are 135 and 175. Course 1

2 -1 Variables and Expressions Additional Example 1 B: Evaluating Algebraic Expressions Evaluate the expression to find the missing values in the table. Course 1 z z 5 + 42 20 20 Substitute for z in z 5 + 42. z = 20; 20 5 + 16 = 20 45 z = 45; 45 __ 5 + 16 = __ 60 z = 60; 60 __ 5 + 16 = __

2 -1 Variables and Expressions Check It Out: Example 1 A Evaluate the expression to find the missing values in the table. Course 1 x x 9 18 2 Substitute for x in x 9. x = 18; 18 9 = 2 36 x = 36; 36 9 = 54 x = 54; 54 9 =

2 -1 Variables and Expressions Check It Out: Example 1 B Evaluate the expression to find the missing values in the table. Course 1 z 8 z + 23 7 64 Substitute for z in 8 z + 23. z = 7; 8 7 + 8 = 64 9 9 8 = __ z = 9; 8 __+ 11 z = 11; 8 11 __ + 8 = __

2 -1 Variables and Expressions You can write multiplication and division expressions without using the symbols and . Instead of. . . x 3 35 ÷ y You can write. . . x 3 x(3) 3 x 35 y Writing Math When you are multiplying a number times a variable, the number is written first. Write “ 3 x” not “x 3. ” Read 3 x as “three x. ” Course 1

2 -1 Variables and Expressions Additional Example 2: Evaluating Expressions with Two Variables A rectangle is 4 units wide. How many square units does the rectangle cover if it is 3, 4, 5, or 6 units long? Make a table to help you find the l w l x w number of square units for each length. 3 4 12 3 x 4= square units 4 4 4 x 4= square units 5 4 5 x 4= square units 6 4 6 x 4= square units Course 1

2 -1 Variables and Expressions Check It Out: Example 2 A rectangle is 3 units wide. How many square units does the rectangle cover if it is 2, 3, 4, or 5 units long? Make a table to help you find the l w l x w number of square units for each length. 2 x 3= square units 3 3 x 3= square units 4 3 4 x 3= square units 5 3 5 x 3= square units 2 3 3 Course 1 6

2 -1 Variables and Expressions Lesson Quiz x x 2 – 5 10 7 5 1. Evaluate the expression to find the missing values in the table. 2. A rectangle is 6 units wide. How many square units does the rectangle cover if it is 2, 3, 4, or 5 units long? Course 1 l w 2 6 3 6 4 6 5 6 l xw